RGD Reference Report - NKCC activity restores muscle water during hyperosmotic challenge independent of insulin, ERK, and p38 MAPK. - Rat Genome Database

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NKCC activity restores muscle water during hyperosmotic challenge independent of insulin, ERK, and p38 MAPK.

Authors: Gosmanov, AR  Schneider, EG  Thomason, DB 
Citation: Gosmanov AR, etal., Am J Physiol Regul Integr Comp Physiol 2003 Mar;284(3):R655-65.
RGD ID: 727466
Pubmed: PMID:12433675   (View Abstract at PubMed)
DOI: DOI:10.1152/ajpregu.00576.2002   (Journal Full-text)

In isosmotic conditions, insulin stimulation of PI 3-K/Akt and p38 MAPK pathways in skeletal muscle inhibits Na(+)-K(+)-2Cl(-) cotransporter (NKCC) activity induced by the ERK1,2 MAPK pathway. Whether these signaling cascades contribute to NKCC regulation during osmotic challenge is unknown. Increasing osmolarity by 20 mosM with either glucose or mannitol induced NKCC-mediated (86)Rb uptake and water transport into rat soleus and plantaris skeletal muscle in vitro. This NKCC activity restored intracellular water. In contrast to mannitol, hyperosmolar glucose increased ERK1,2 and p38 MAPK phosphorylation. Glucose, but not mannitol, impaired insulin-stimulated phosphorylation of Akt and p38 MAPK in the plantaris and soleus muscles, respectively. Hyperosmolarity-induced NKCC activation was insensitive to insulin action and pharmacological inhibition of ERK1,2 and p38 MAPK pathways. Paradoxically, cAMP-producing agents, which stimulate NKCC activity in isosmotic conditions, suppressed hyperosmolar glucose- and mannitol-induced NKCC activity and prevented restoration of muscle cell volume in hyperosmotic media. These results indicate that NKCC activity helps restore muscle cell volume during hyperglycemia. Moreover, hyperosmolarity activates NKCC regulatory pathways that are insensitive to insulin inhibition.



Objects referenced in this article
Gene Slc12a1 solute carrier family 12 member 1 Rattus norvegicus

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